I read somewhere that the mirror defect was specific to Hubble, because it was designed to focus at infinity while the Keyhole mirrors focused at 400 miles or w

I read somewhere that the mirror defect was specific to Hubble, because it was designed to focus at infinity while the Keyhole mirrors focused at 400 miles or whatever is orbital height. So it had a different curvature but the custom grind rig for that modified curvature was constructed erroneously. There is definitely public discussion of such details if you dig.